“Everyone in the Stanford Football family is deeply saddened by the passing of Chester McGlockton,” head coach David Shaw said in a statement. “For the past two seasons, Chester has been a valuable member of our football staff and a wonderful friend to us all.”

“The thoughts and prayers of the Raider Nation are with the McGlockton family during this difficult time,” Raiders CEO Amy Trask added in a statement from the Raiders.

This 2002 photo provided by the NFL shows Chester McGlockton, then with the Denver Broncos. The Stanford defensive assistant and four-time Pro Bowl defensive lineman with the Raiders passed away on Tuesday night of a heart attack.

Image 1 of 8 - Chester McGlockton

This 2002 photo provided by the NFL shows Chester McGlockton, then with the Denver Broncos. The Stanford defensive assistant and four-time Pro Bowl defensive lineman with the Raiders passed away on Tuesday night of a heart attack.